public class TestDistance {
	public static void main(String[] args) {
		System.out.println(getDistance(1,2,3,4));
	}

	public static double getDistance(double x1,double y1,double x2,double y2) {
		double tx = (x2-x1)*(x2-x1);
		double ty = (y2-y1)*(y2-y1);
		return Math.sqrt(tx+ty);
	}
}